feat: Implement comparison of matcher

README.md

@@ -374,6 +374,8 @@ about any of them, make sure to [consult the documentation][rubydocs]!
   tests usage of `validates_numericality_of`.
 * **[validate_presence_of](lib/shoulda/matchers/active_model/validate_presence_of_matcher.rb)**
   tests usage of `validates_presence_of`.
+* **[validate_comparison_of](lib/shoulda/matchers/active_model/validate_comparison_of_matcher.rb)**
+  tests usage of `validates_comparison_of`.
 
 ### ActiveRecord matchers
 

lib/shoulda/matchers/active_model.rb

@@ -21,8 +21,9 @@
 require 'shoulda/matchers/active_model/validate_acceptance_of_matcher'
 require 'shoulda/matchers/active_model/validate_confirmation_of_matcher'
 require 'shoulda/matchers/active_model/validate_numericality_of_matcher'
+require 'shoulda/matchers/active_model/validate_comparison_of_matcher'
+require 'shoulda/matchers/active_model/comparison_matcher'
 require 'shoulda/matchers/active_model/numericality_matchers/numeric_type_matcher'
-require 'shoulda/matchers/active_model/numericality_matchers/comparison_matcher'
 require 'shoulda/matchers/active_model/numericality_matchers/odd_number_matcher'
 require 'shoulda/matchers/active_model/numericality_matchers/even_number_matcher'
 require 'shoulda/matchers/active_model/numericality_matchers/only_integer_matcher'

lib/shoulda/matchers/active_model/comparison_matcher.rb

@@ -0,0 +1,158 @@
+require 'active_support/core_ext/module/delegation'
+
+module Shoulda
+  module Matchers
+    module ActiveModel
+      # @private
+      class ComparisonMatcher < ValidationMatcher
+        ERROR_MESSAGES = {
+          :> => {
+            label: :greater_than,
+            assertions: [false, false, true],
+          },
+          :>= => {
+            label: :greater_than_or_equal_to,
+            assertions: [false, true, true],
+          },
+          :< => {
+            label: :less_than,
+            assertions: [true, false, false],
+          },
+          :<= => {
+            label: :less_than_or_equal_to,
+            assertions: [true, true, false],
+          },
+          :== => {
+            label: :equal_to,
+            assertions: [false, true, false],
+          },
+          :!= => {
+            label: :other_than,
+            assertions: [true, false, true],
+          },
+        }.freeze
+
+        delegate :failure_message, :failure_message_when_negated, to: :submatchers
+
+        def initialize(matcher, value, operator)
+          super(nil)
+          unless matcher.respond_to? :diff_to_compare
+            raise ArgumentError, 'matcher is invalid'
+          end
+
+          @matcher = matcher
+          @value = value
+          @operator = operator
+          @message = ERROR_MESSAGES[operator][:label]
+        end
+
+        def simple_description
+          description = ''
+
+          if expects_strict?
+            description << ' strictly'
+          end
+
+          description +
+            "disallow :#{attribute} from being a number that is not " +
+            "#{comparison_expectation} #{@value}"
+        end
+
+        def for(attribute)
+          @attribute = attribute
+          self
+        end
+
+        def with_message(message)
+          @expects_custom_validation_message = true
+          @message = message
+          self
+        end
+
+        def expects_custom_validation_message?
+          @expects_custom_validation_message
+        end
+
+        def matches?(subject)
+          @subject = subject
+          build_option_value
+          submatchers.matches?(subject)
+        end
+
+        def does_not_match?(subject)
+          @subject = subject
+          build_option_value
+          submatchers.does_not_match?(subject)
+        end
+
+        def comparison_description
+          "#{comparison_expectation} #{@value}"
+        end
+
+        def submatchers
+          @_submatchers ||= NumericalityMatchers::Submatchers.new(build_submatchers)
+        end
+
+        private
+
+        def build_submatchers
+          comparison_combos.map do |diff, submatcher_method_name|
+            matcher = __send__(submatcher_method_name, diff, nil)
+            matcher.with_message(@message, values: { count: @value })
+            matcher
+          end
+        end
+
+        def comparison_combos
+          diffs_to_compare.zip(submatcher_method_names)
+        end
+
+        def submatcher_method_names
+          assertions.map do |value|
+            if value
+              :allow_value_matcher
+            else
+              :disallow_value_matcher
+            end
+          end
+        end
+
+        def assertions
+          ERROR_MESSAGES[@operator][:assertions]
+        end
+
+        def build_option_value
+          @value = case @value
+                   when Proc then @value.call(@subject)
+                   when Symbol then @subject.send(@value)
+                   else @value
+                   end
+        end
+
+        def diffs_to_compare
+          diff_to_compare = @matcher.diff_to_compare
+          values = case @value
+                   when String then diffs_when_string(diff_to_compare)
+                   else [-1, 0, 1].map { |sign| @value + (diff_to_compare * sign) }
+                   end
+
+          if @matcher.given_numeric_column?
+            values
+          else
+            values.map(&:to_s)
+          end
+        end
+
+        def diffs_when_string(diff_to_compare)
+          [-1, 0, 1].map do |sign|
+            @value[0..-2] + (@value[-1].ord + diff_to_compare * sign).chr
+          end
+        end
+
+        def comparison_expectation
+          ERROR_MESSAGES[@operator][:label].to_s.tr('_', ' ')
+        end
+      end
+    end
+  end
+end

lib/shoulda/matchers/active_model/numericality_matchers/range_matcher.rb

@@ -59,7 +59,7 @@ def submatcher_combos
           end
 
           def build_comparison_submatcher(value, operator)
-            NumericalityMatchers::ComparisonMatcher.new(@numericality_matcher, value, operator).
+            ComparisonMatcher.new(@numericality_matcher, value, operator).
               for(@attribute).
               with_message(@message).
               on(@context)

lib/shoulda/matchers/active_model/numericality_matchers/submatchers.rb

@@ -13,29 +13,46 @@ def matches?(subject)
             failing_submatchers.empty?
           end
 
+          def does_not_match?(subject)
+            @subject = subject
+            not_failing_submatchers.empty?
+          end
+
           def failure_message
-            last_failing_submatcher.failure_message
+            failing_submatcher.failure_message
           end
 
           def failure_message_when_negated
-            last_failing_submatcher.failure_message_when_negated
+            not_failing_submatcher.failure_message_when_negated
           end
 
           def add(submatcher)
             @submatchers << submatcher
           end
 
-          def last_failing_submatcher
-            failing_submatchers.last
-          end
-
           private
 
           def failing_submatchers
             @_failing_submatchers ||= @submatchers.reject do |submatcher|
               submatcher.matches?(@subject)
             end
           end
+
+          def not_failing_submatchers
+            @_not_failing_submatchers ||= @submatchers.reject do |submatcher|
+              submatcher.does_not_match?(@subject)
+            end
+          end
+
+          def failing_submatcher
+            failing_submatchers.last
+          end
+
+          def not_failing_submatcher
+            not_failing_submatchers.detect { |submatcher|
+              submatcher.instance_of?(DisallowValueMatcher)
+            } || not_failing_submatchers.first
+          end
         end
       end
     end